1. Field of the Invention
The present invention relates to electric actuator technology, and more particularly to an electric actuator assembly, which comprises a one-way bearing to provide a braking effect when the driving power is off, preventing falling of the load and assuring the operational safety.
2. Description of the Prior Art
Electric actuators with different mechanical designs and transmission mechanisms are widely used in electric beds, electric massage chairs, patient lifts, fitness machines, and rehabilitation machines. These electric actuators commonly use a motor to drive a transmission mechanism, causing an extension rod to extend or to retract for adjustment of the elevation or angle of the electric bed, electric massage chair, etc.
The power transmission of electric actuator conventionally consists of a worm and a worm gear for delivering the driving power of a motor to rotate the lead screw, moving the extension rod linearly to lift or lower a connecting part or supporting frame of a mechanism. Normally, the worm is made of metal, and the worm gear is made from a plastic material. When the driving power is off, the gravity of the load can force the lead screw to rotate in the reversed direction, causing falling of the connecting part or supporting frame of the lifting mechanism. In order to eliminate this problem, a brake mechanism is normally used for holding the connecting part or supporting frame of the lifting mechanism in position when the driving power is off. However, this brake mechanism occupies much installation space, affects spatial arrangement of other components, even redesigning for the specification and tooling, and results in restricting the application flexibility and increasing the manufacturing cost of the electric actuator. An improvement in this regard is desired.